Fine-scale altitudinal gradients influence the relationships between structural attributes and aboveground biomass in Central Africa

2021 ◽  
pp. 1-9
Author(s):  
Eymard Menanzala Miambam ◽  
Grace Jopaul Loubota Panzou ◽  
Yannick Enock Bocko ◽  
Jean Joël Loumeto
Keyword(s):  
Aboveground Biomass ◽  
Altitudinal Gradient ◽  
Central Africa ◽  
Permanent Plots ◽  
Stem Density ◽  
Clear Understanding ◽  
Fine Scale ◽  
Remotely Sensed Data ◽  
Altitudinal Gradients ◽  
The Republic

There is increasing interest in altitude effects on structural attributes and aboveground biomass (AGB) in tropical forests. However, we continue to lack a clear understanding of relationships between structural attributes and AGB along altitudinal gradients in Central Africa. Using a new network of 76 permanent plots of 0.5 ha, the relationships between structural attributes and AGB were explored along fine-scale altitudinal gradients in the Republic of Congo. We chose four fine-scale altitudinal gradients (71–350 m, 350–550 m, 550–650 m, and 650–853 m) and measured the diameter and heights of 4192 trees with a ≥10 cm diameter and calculated the structural attributes and the AGB for each 0.5 ha plot. For a given diameter, trees were shorter and had narrower crowns in the altitudinal gradient of 71–350 m than in the other altitudinal gradients. The relationships between structural attributes and AGB differ along fine-scale altitudinal gradients, with higher stem density, wood density, crown depth, and AGB for the altitudinal gradient of 71–350 m. These results provide important advances in our understanding of the relationships between structural attributes and AGB along fine-scale altitudinal gradients in Central Africa. They should improve AGB estimates for the low altitudinal gradient when combined with other field and remotely sensed data sets in Central Africa.

scholarly journals Quantifying Aboveground Biomass of Shrubs Using Spectral and Structural Metrics Derived from UAS Imagery

2020 ◽  
Vol 12 (14) ◽  
pp. 2199 ◽  
Author(s):  
Lucy G. Poley ◽  
David N. Laskin ◽  
Gregory J. McDermid
Keyword(s):  
Linear Regression ◽  
Aboveground Biomass ◽  
Regression Models ◽  
Vegetation Index ◽  
Spatial Information ◽  
Structural Data ◽  
Biomass Estimation ◽  
Fine Scale ◽  
Linear Regression Models ◽  
Remotely Sensed Data

Shrub-dominated ecosystems support biodiversity and play an important storage role in the global carbon cycle. However, it is challenging to characterize biophysical properties of low-stature vegetation like shrubs from conventional ground-based or remotely sensed data. We used spectral and structural variables derived from high-resolution unmanned aerial system (UAS) imagery to estimate the aboveground biomass of shrubs in the Betula and Salix genera in a montane meadow in Banff National Park, Canada using an area-based approach. In single-variable linear regression models, visible light (RGB) indices outperformed multispectral or structural data. A linear model based on the red ratio vegetation index (VI) accumulated over shrub area could model biomass (calibration R2 = 0.888; validation R2 = 0.774) nearly as well as the top multivariate linear regression models (calibration R2 = 0.896; validation R2 > 0.750), which combined an accumulated RGB VI with a multispectral metric. The excellent performance of accumulated RGB VIs represents a novel approach to fine-scale vegetation biomass estimation, fusing spectral and spatial information into a single parsimonious metric that rivals the performance of more complex multivariate models. Methods developed in this study will be relevant to researchers interested in estimating fine-scale shrub aboveground biomass within a range of ecosystems.

scholarly journals Tree Species Diversity, Composition and Aboveground Biomass Across Dry Forest Land-Cover Types in Coastal Ecuador

2021 ◽  
Vol 14 ◽  
pp. 194008292199541
Author(s):  
Xavier Haro-Carrión ◽  
Bette Loiselle ◽  
Francis E. Putz
Keyword(s):  
Species Diversity ◽  
Land Cover ◽  
Community Composition ◽  
Aboveground Biomass ◽  
Tree Species ◽  
Dry Forest ◽  
Stem Density ◽  
Tree Species Diversity ◽  
Land Cover Types ◽  
Schizolobium Parahyba

Tropical dry forests (TDF) are highly threatened ecosystems that are often fragmented due to land-cover change. Using plot inventories, we analyzed tree species diversity, community composition and aboveground biomass patterns across mature (MF) and secondary forests of about 25 years since cattle ranching ceased (SF), 10–20-year-old plantations (PL), and pastures in a TDF landscape in Ecuador. Tree diversity was highest in MF followed by SF, pastures and PL, but many endemic and endangered species occurred in both MF and SF, which demonstrates the importance of SF for species conservation. Stem density was higher in PL, followed by SF, MF and pastures. Community composition differed between MF and SF due to the presence of different specialist species. Some SF specialists also occurred in pastures, and all species found in pastures were also recorded in SF indicating a resemblance between these two land-cover types even after 25 years of succession. Aboveground biomass was highest in MF, but SF and Tectona grandis PL exhibited similar numbers followed by Schizolobium parahyba PL, Ochroma pyramidale PL and pastures. These findings indicate that although species-poor, some PL equal or surpass SF in aboveground biomass, which highlights the critical importance of incorporating biodiversity, among other ecosystem services, to carbon sequestration initiatives. This research contributes to understanding biodiversity conservation across a mosaic of land-cover types in a TDF landscape.

scholarly journals Presidential Tenure and Constitutional Provisions: Recent Evidence from Central Africa

2020 ◽  
Vol 55 (3) ◽  
pp. 272-290 ◽  
Author(s):  
Mark Dawson ◽  
Daniel J. Young
Keyword(s):  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Central Africa ◽  
Term Limits ◽  
Republic Of Congo ◽  
Term Limit ◽  
Developing Democracies ◽  
The Republic ◽  
Constitutional Factor

Constitutions around Africa have been repeatedly tested on the issue of presidential term limits. We explore the four most recent cases of African presidents facing the end of their constitutionally mandated limit, all of which developed in Central Africa. Burundi, Rwanda, the Republic of Congo, and the Democratic Republic of Congo all adopted constitutions limiting presidential tenure to two terms; yet, in 2015, when these limits were approaching, none of the sitting presidents simply stood down. Our analysis focuses on the constitutional provisions meant to protect the two-term limit, the strategies employed by each of the four presidents, and the difficulty they faced in pursuing extended tenure. We find that constitutional provisions do constrain, but not always to the expected degree. Our analysis adds a consideration of a foundational constitutional factor to the growing literature on term limits in Africa, with implications for other regions of newly developing democracies.

scholarly journals What can the occult do for you?

2016 ◽  
Vol 11 (S321) ◽  
pp. 248-250
Author(s):  
B. W. Holwerda ◽  
W. C. Keel
Keyword(s):  
Interstellar Dust ◽  
Probability Function ◽  
Great Accuracy ◽  
Extinction Curve ◽  
Clear Understanding ◽  
Fine Scale ◽  
Grain Composition ◽  
Field Unit ◽  
Integral Field

AbstractInterstellar dust is still a dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy.Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses Hubble to map the distribution of dust in foreground galaxies in fine (<100 pc) detail. Integral Field Unit (IFU) observations will map the effective extinction curve, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy.The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: geometry, a probability function of dimming as a function of galaxy mass and radius, and its dependence on wavelength.

EVALUATING THE EFFICIENCY OF FEEDING BROILER CHICKENS OF THE ARBOR ACRES CROSS IN HOT CLIMATIC CONDITIONS OF THE REPUBLIC OF CHAD

2020 ◽  
pp. 72-82
Author(s):  
M.V. LAZKO ◽  
◽  
ADAM A. ABDERAKHIM
Keyword(s):  
Environmental Factors ◽  
Biochemical Parameters ◽  
Broiler Chickens ◽  
Central Africa ◽  
Live Weight ◽  
Climatic Conditions ◽  
Geochemical Conditions ◽  
Blood Biochemical ◽  
The Republic ◽  
The University

The paper presents the results of evaluating the efficiency of feed rations offered to broilers of the Arbor Acres cross, formed taking into account the climatic, geochemical conditions of Central Africa and its native food flora. The study was conducted on the basis of an experimental farm at the University of N’Djamena, the Republic of Chad. In the experiment, the authors used five formulas of feed rations, which are currently used by farms in the Republic of Chad for growing broiler chickens. They mainly contain locally availble ingredients. To increase the resistance of the poultry organism to unfavorable environmental factors, the chickens of the control and experimental groups were given “TETRACOLIVIT” and “AMIN’TOTAL” vitamins. The efficiency of feed rations was evaluated by determining the age dynamics of live weight, average weekly gains in live weight and blood biochemical parameters of broiler chickens of the Arbor Acres cross from 1 to 42 days of life. The formula of feed ration No. 1 proved to be the most effective in terms of the cross productivity.

scholarly journals What controls local-scale aboveground biomass variation in central Africa? Testing structural, composition and architectural attributes

2018 ◽  
Vol 429 ◽  
pp. 570-578 ◽  
Author(s):  
Grace Jopaul Loubota Panzou ◽  
Adeline Fayolle ◽  
Ted R. Feldpausch ◽  
Gauthier Ligot ◽  
Jean-Louis Doucet ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Central Africa ◽  
Local Scale ◽  
Structural Composition

scholarly journals Upscale or downscale: applications of fine scale remotely sensed data to Chagas disease in Argentina and schistosomiasis in Kenya

2006 ◽  
Vol 1 (1) ◽  
pp. 49 ◽  
Author(s):  
Uriel Kitron ◽  
Julie A. Clennon ◽  
M. Carla Cecere ◽  
Ricardo E. Gürtler ◽  
Charles H. King ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Remotely Sensed ◽  
Fine Scale ◽  
Remotely Sensed Data

Sudan

2020 ◽  
Author(s):  
Marius Schneider ◽  
Vanessa Ferguson
Keyword(s):  
Red Sea ◽  
South Sudan ◽  
Central Africa ◽  
Eastern Africa ◽  
North Eastern ◽  
The Republic

Sudan is situated in north-eastern Africa bordered by the Red Sea, Egypt, Libya, Chad, Central Africa Republic, South Sudan, Ethiopia, and Eritrea. It has an area of 1,886 million square kilometres (km) and an estimated 2019 population of 42.81 million. South Sudan gained independence from Sudan on 9 July 2011, and as such the provisions only relate to Sudan (North), which is now formally known as the Republic of Sudan. The capital of Sudan is Khartoum. The working week in Sudan is from Saturday to Wednesday with business hours beginning at 0800 and ending at 1630, Thursday’s hours are from 0800 to 1300, whilst Friday is day off. The currency in Sudan is the Sudanese pound (SDG/Ls).

Integrating field data

2010 ◽  
Author(s):  
Ned Horning ◽  
Julie A. Robinson ◽  
Eleanor J. Sterling ◽  
Woody Turner ◽  
Sacha Spector
Keyword(s):  
South Africa ◽  
Habitat Use ◽  
Vegetation Type ◽  
Remotely Sensed ◽  
Battery Life ◽  
Clear Understanding ◽  
Remotely Sensed Data ◽  
Human Settlements ◽  
Ecological Gradient ◽  
Landsat 7

While the savannah elephant (Loxodonta africana) is listed by the International Union for Conservation of Nature (IUCN) as “vulnerable” because of declining abundance in some regions of Africa (Blanc 2008), populations in some protected areas of South Africa are growing rapidly (van Aarde and Jackson 2007). These populations can cause extensive modification of vegetation structure when their density increases (Owen-Smith 1996; Whyte et al. 2003; Guldemond and van Aarde 2007). Management methods such as culling, translocation, and birth control have not reduced density in some cases (van Aarde et al. 1999; Pimm and van Aarde 2001). Providing more space for elephants is one alternative management strategy, yet fundamental to this strategy is a clear understanding of habitat and landscape use by elephants. Harris et al. (2008) combined remotely sensed data with Global Positioning System (GPS) and traditional ethological observations to assess elephant habitat use across three areas that span the ecological gradient of historical elephant distribution. They explored influences on habitat use across arid savannahs (Etosha National Park in Namibia) and woodlands (Tembe Elephant Park in South Africa and Maputo Elephant Reserve in Mozambique). The researchers focused on three main variables—distance to human settlements, distance to water, and vegetation type. The authors used Landsat 7 ETMþ imagery to create vegetation maps for each location, employing supervised classification and maximum likelihood estimation. Across all sites, they recorded the coordinates of patches with different vegetation and of vegetation transitions to develop signatures for the maps. Elephants do not use all vegetation types, and it can be expedient to focus on presence rather than both presence and absence. Accordingly, the researchers used GPS to record the locations of elephants with the aim of identifying important land cover types for vegetation mapping. The authors mapped water locations in the wet and dry seasons using remotely sensed data and mapped human settlements using GPS, aerial surveys, and regional maps. They tracked elephants with radiotelemetry collars that communicated with the ARGOS satellite system, sending location data for most of the elephants over 24 h, and then remaining quiescent for the next 48 h to extend battery life.

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